2004 ISUZU TF SERIES fuel type

6A – 4 ENGINE MECHANICAL
MAIN DATA AND SPECIFICATIONS
Engine model
Item 4JA1T (L) 4JA1TC
Engine type
Combustion chamber type
Cylinder liner type
Timing gear train system Four-cycle, overhead valve, water cooled
Direct injection
Dry type, chrome plated
Gear drive
No. of cylinders-bore
stroke mm (in) 4 – 93
92 (3.66
3.62)
No. of piston rings Compression ring: 2 / Oil ring: 1
Total piston displacement cm3 (in3)
Compression ratio (to 1) 2,499(152.4)
18.5
Compression pressure Mpa(kg/cm2/psi) 3.0 (31.0/441) – 200 rpm
Engine weight (dry) kg (lb) Approximately 239 (527)
Fuel injection order 1 – 3 – 4 - 2
Fuel injection timing BTDC deg 8 -
Specified fuel type
Idling speed rpm

Valve clearances (At cold): Intake mm (in)
Exhaust mm (in)
Intake valves Open at (BTDC) deg
Close at (ABDC) deg
Exhaust valves Open at (BBDC) deg
Close at (ATDC) deg
Fuel system JIS No. 2, DIN/EN590, GB252-1944 Diesel fuel
730  25 (A/C Off)
850  25 (A/C ON)
0.4 (0.016)
0.4 (0.016)
24.5
55.5
54.0
26.0

Injection pump type BOSCH distributor VE type BOSCH distributor VP44 type
Governor type Mechanical (Half all speed
type) Electronically controled
Injection nozzle type
Injection nozzle opening pressure Hole with 5 orifices

Mpa(kg/cm2/psi) 1st 19.1 (195 / 2,773) 1st 19.0 (194 / 2,755)
2nd (Reference)
25.527.0
(260275 / 3,7023,920) 2nd (Reference)
34.035.5
(347362 / 4,9365,154)
Main fuel filter type
Lubricating system
Lubricating method Cartridge paper element and water separator

Pressure circulation
Specified engine oil (API grade) ISUZU genuine 10W – 30 (API CD of ACEA B2/B3)

6A – 6 ENGINE MECHANICAL
MAIN DATA AND SPECIFICATIONS
Engine model
Item 4JH1TC
Engine type Four-cycle, overhead valve, water cooled
Combustion chamber type Direct injection
Cylinder liner type
Timing gear train system Dry type, chrome plated
Gear drive
No. of cylinders-bore
stroke mm (in) 4 – 95.4
104.9 (3.76
4.13)
No. of piston rings Compression ring: 2 / Oil ring: 1
Total piston displacement liter
Compression ratio (to 1) 2,999
18.3
Compression pressure MPa(kg/cm2/psi) 3.0 (31.0/441) – 200 rpm
Engine weight (dry) kg (lb) MT : Approximately 249 (549)
AT : Approximately 236 (520)
Fuel injection order 1 – 3 – 4 - 2
Specified fuel type JIS No.2, DIN/EN590, GB252-1944 Diesel fuel
Idling speed rpm
700
25 (A/C OFF)
800
25 (A/C ON)
Valve clearances (At cold): Intake mm (in)
Exhaust mm (in)
Intake valves Open at (BTDC) deg
Close at (ABDC) deg
Exhaust valves Open at (BBDC) deg
Close at (ATDC) deg
Fuel system
Injection pump type 0.4 (0.016)
0.4 (0.016)
24.5
55.5
54.0
26.0

BOSCH distributor VP44 type
Injection nozzle type
Injection nozzle opening pressure
MPa(kg/cm
2/psi)Hole with 5 orifices

1st 19.5 (199/2,828)
2nd (Reference) 34.335.8 (350365/4,9805,197)
Main fuel filter type
Lubricating system
Lubricating method Cartridge paper element and water separator

Pressure circulation
Specified engine oil (API grade) ISUZU genuine 10W – 30 (API CD of ACEA B2/B3)
Oil pump type
Oil filter type Gear
Cartridge paper element
Oil capacity lit (US/UK gal)
6.2 (1.64/1.36) (For 4
2)
7.0 (1.85/1.54) (For 4
4)
Oil cooler type Water cooled

6A – 36 ENGINE MECHANICAL
GENERAL DESCRIPTION









RTW46AMF000401

The 4J series automotive diesel engine has special designed combustion chambers in the piston. This design
provides superior fuel economy over a wide range of driving conditions.
Auto-thermatic pistons with cast steel struts are used to reduce thermal expansion and resulting engine noise when
the engine is cold.
Chrome plated dry type cylinder liners provide the highest durability.
The laminated steel sheet cylinder head gasket is very durable and, to increase the head gasket reliability.
The crankshaft has been tufftrided to provide a longer service life. Because the crankshaft is tufftrided, it cannot be
reground.
The 4JA1T(L) engine is equipped with the BOSCH VE-Type distributor injection pump.
The 4JH1TC and 4JA1TC engine is equipped with the BOSCH VP44-Type distributor injection pump.
The engine is turbocharger equipped.

FUEL SYSTEM 6C – 3

MAIN DATA AND SPECIFICATIONS
Description Item
4JA1T (L) 4JA1TC 4JH1TC
Injection pump type
Bosch distributor
VE type Bosch distributor VP44 type
Governor type Mechanical variable
(Half speed oil
pressure) Electrical controled
Timer type Oil pressure Electrical controled
Fuel feed pump type Vane with input shaft
Injection nozzle type Hole type
Number of injection nozzle orifices 5
Injection nozzle orifices
Inside diameter mm (in) 0.19 (0.0075) 0.17 (0.0067) 0.21 (0.0083)
19.1 (195) 19.0 (194) 19.5 (199) Injection nozzle designed operating
pressure MPa (kg/cm2) 1st
2nd 25.0 (255) 33.5 (328) 33.8 (331)
Main fuel filter type Disposable cartridge paper element


Precautions
When working on the fuel system, there are several things
to keep in mind:

Any time the fuel system is being worked on,
disconnect the negative battery cable except fo
r
those tests where battery voltage is required.

Always keep a dry chemical (Class B) fire
extinguisher near the work area.
 Replace all pipes with the same pipe and fittings that
were removed.
 Clean and inspect “O" rings. Replace if required.
 Always relieve the line pressure before servicing any
fuel system components.
 Do not attempt repairs on the fuel system until you
have read the instructions and checked the pictures
relating to that repair.
 Adhere to all Notices and Cautions.

NOTE:
Injection nozzle adjustment is possible only on the 4JA1L
engine.

FUEL SYSTEM 6C – 5


FUEL FILTER AND WATER SEPARATOR
As the inside of the injection pump is lubricated by the fuel which it is pumping, the fuel must be perfectly clean. The
fuel filter and the water separator remove water particles and other foreign material from the fuel before it reaches
the injection pump.
The water separator has an internal float. When the float reaches the specified level, a warning light comes on to
remind you to drain the water from the water separator.
A diaphragm type priming pump is installed at the top of the fuel filter. It is used during the air bleeding procedures.

(Except EURO III model)


RTW36CLF000701

FUEL SYSTEM 6C – 7
INJECTION PUMP


RTW46CLF000201

4JA1T(L):
A Bosch Distributor Type Injection Pump is used. A single reciprocating/revolving plunger delivers the fuel uniformly
to the injection nozzles, regardless of the number of cylinders.
The governor, the injection timer, and the feed pump are all contained in the injection pump housing. The injection
pump is compact, light weight, and provides reliable high-speed operation.
The vacuum-type fast idle actuator increases the engine idling speed to provide the additional power required to
operate the air conditioner.
Fast idler diaphragm movement is caused by changes in the negative pressure created by the engine’s vacuum
pump.
The diaphragm motion is transferred to the injection pump control lever to increase or decrease the idling speed.

4JA1TC/4JH1TC:
The Bosch VP44 injection pump is electronically controlled. The pump controller combine to injection pump.
Signals from the pump controller are sent to the engine control module (ECM). In response to these signals, the
ECM selects the optimum fuel injection timing and volume for the existing driving conditions.

6C – 8 FUEL SYSTEM
INJECTION NOZZLE (4JA1L)

RTW46CM F000301
NOTE:


Injection nozzle adjustment is possible only on the 4JA1L engine.

A hole (with 5 orifices) type injection nozzle. It consists of the nozzle body and the needle valve assembly.
The injection nozzle assembly sprays pressurized fuel from the injection pump into the combustion chamber through
the nozzle body injection orifice.

6C – 18 FUEL SYSTEM
FUEL FILLER CAP




RTW36CSH000401
Legend

(1)
Pressure Valve

(2)
Vacuum Valve

(3)
Seal Ring


General Description
A vacuum valve and pressure valve are built into the fuel filler
cap which adjusts the fuel pressure in the fuel tank to prevent
fuel tank damage.


Inspection
The fuel filler cap must be inspected for seal condition.
The fuel filler cap must be replaced if found defective

CAUTION: A replacement fuel filler cap must be the same
as the original. The fuel filler cap valve was designed
primarily for this application and must be replaced with
the same type or decreased engine performance may
occur.